The proposed research will examine the mechanism by which epidermal growth factor (EGF), acting through intracellular calcium ion (Ca++), stimulates the expression of the prolactin (PRL) gene in GH3 cells. In particular, the experiments outlined in this proposal re designed to investigate the possible involvement of non-histone chromatin (NHC) proteins in the stimulation of the prolactin gene by EGF plus Ca++. The two major aims of the proposal are the demonstration of in vitro binding of specific NHC proteins to discrete regions of a cloned PRL genomic DNA and to relate the NHC protein-PRL DNA binding data to the mechanism of action of EGF plus Ca++. The latter aim will be done by looking for changes in the extent of NHC-PRL DNA binding during treatment with EGF plus Ca++, examining the role of a Ca++ calmodulin complex in NHC-PRL DNA binding, and examining whether the extent of phosphorylation or the synthesis of a specific PRL gene-binding protein is altered during treatment with EGF plus Ca++.